Technical Field
The present disclosure relates to a molding device and molding method of a fuel tank flange section.
Related Art
Conventionally, in fuel tanks molded of resin, sheet shaped parisons (sheet bodies) formed of molten resin are respectively vacuum shaped by an upper mold and a lower mold, and a hollow bodied fuel tank is molded by closing the upper mold and the lower mold together. When this is performed, a flange section is formed to the fuel tank by joining together respective end portions of the sheet bodies (see, for example, Japanese Patent Application Laid-Open (JP-A) No. 2008-155588).
When forming the flange section to the fuel tank, the end portions of the sheet bodies (molten resin) that have been shaped by the upper mold and the lower mold are joined by closing the upper mold and the lower mold, each provided with a flange mold face, together and molding the flange section into a specific shape. When this is performed, recessed portions are formed on the surface of the sheet bodies by local variation in the shrinkage arising from heat radiating from the sheet bodies. There is accordingly a concern that air remains present at positions inside the recessed portions of the sheet body, at the inside of any flange sections that have been molded by joining together sheet bodies.
The joint strength of the flange section decreases when air remains between the joint faces of flange sections in this manner.